1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device, and particularly relates to a method for forming a conductive layer.
2. Description of the Related Art
In manufacture of a semiconductor device, after forming a conductive layer, a wiring in a desired shape is formed by etching the conductive layer with a resist as a mask.
For etching a conductive layer, dry etching is often used. Dry etching is a method in which an active species excited by plasma discharge is pulled toward an object to be processed by applying a bias, and the active species is reacted with the object to be processed to etch the object to be processed. When such dry etching is used to etch a conductive layer, a reaction product is formed by a reaction of an active species with the conductive layer. Although most of the reaction product is evacuated during etching, a portion thereof adheres to a resist used as a mask. Then, most of the reaction product adhering to the resist is usually removed when the resist used as a mask is removed. However, a portion of the reaction product remains adhering to the conductive layer and standing in a perpendicular direction. The thus reaction product remaining on the conductive layer may cause defects of a semiconductor device. Therefore, it is necessary to remove the reaction product. However, it is difficult to remove the reaction product adhering to the conductive layer and standing in a perpendicular direction by highly anisotropic etching such as dry etching.
In order to solve the problem described above, for example, in Patent Document 1, a method for manufacturing a semiconductor device is disclosed in which a reaction product is removed by using a hydrofluoric acid vapor treatment.
However, in order to remove a reaction product by the method as in Patent Document 1, it is necessary to provide a new apparatus for hydrofluoric acid vapor treatment so that the cost of manufacturing equipment is increased. Therefore, development of a method for manufacturing a semiconductor device is required in order to remove a reaction product more easily.
(Patent Document 1) Japanese Patent Application Laid-Open No. 9-213703